Faculty Publications, College of DentistryCopyright (c) 2016 University of Nebraska - Lincoln All rights reserved.http://digitalcommons.unl.edu/dentistryfacpub
Recent documents in Faculty Publications, College of Dentistryen-usSat, 02 Jul 2016 02:01:44 PDT3600Greatwall and Polo-like Kinase 1 Coordinate to Promote
Checkpoint Recoveryhttp://digitalcommons.unl.edu/dentistryfacpub/21
http://digitalcommons.unl.edu/dentistryfacpub/21Thu, 30 Jun 2016 12:24:25 PDT
Checkpoint recovery upon completion of DNA repair allows the cell to return to normal cell cycle progression and is thus a crucial process that determines cell fate after DNA damage. We previously studied this process in Xenopus egg extracts and established Greatwall (Gwl) as an important regulator. Here we show that preactivated Gwl kinase can promote checkpoint recovery independently of cyclin-dependent kinase 1 (Cdk1) or Plx1 (Xenopus polo-like kinase 1), whereas depletion of Gwl from extracts exhibits no synergy with that of Plx1 in delaying checkpoint recovery, suggesting a distinct but related relationship between Gwl and Plx1. In further revealing their functional relationship, we found mutual dependence for activation of Gwl and Plx1 during checkpoint recovery, as well as their direct association. We characterized the protein association in detail and recapitulated it in vitro with purified proteins, which suggests direct interaction. Interestingly, Gwl interaction with Plx1 and its phosphorylation by Plx1 both increase at the stage of checkpoint recovery. More importantly, Plx1-mediated phosphorylation renders Gwl more efficient in promoting checkpoint recovery, suggesting a functional involvement of such regulation in the recovery process. Finally, we report an indirect regulatory mechanism involving Aurora A that may account for Gwl-dependent regulation of Plx1 during checkpoint recovery. Our results thus reveal novel mechanisms underlying the involvement of Gwl in checkpoint recovery, in particular, its functional relationship with Plx1, a well characterized regulator of checkpoint recovery. Coordinated interplays between Plx1 and Gwl are required for reactivation of these kinases from the G2/M DNA damage checkpoint and efficient checkpoint recovery.
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Aimin Peng et al.A dentigerous cyst associated with bilaterally
impacted mandibular canines in a girl:
a case reporthttp://digitalcommons.unl.edu/dentistryfacpub/20
http://digitalcommons.unl.edu/dentistryfacpub/20Thu, 30 Jun 2016 12:19:31 PDTIntroduction: A dentigerous cyst is the most common developmental odontogenic cyst and is frequently noted as an incidental finding on radiographs. The most common teeth affected are impacted mandibular third molars and permanent maxillary canines. This case involves a dentigerous cyst encompassing the right and left impacted mandibular canines and crossing the midline. This is, to the best of our knowledge, the first reported case of a dentigerous cyst encompassing non-adjacent teeth and crossing the midline.

Case presentation: The patient presented to our orthodontic clinic for treatment of malocclusion. The patient was a 10-year, one-month-old Caucasian girl with a dentigerous cyst encompassing the right and left impacted mandibular canines and crossing the midline.

Conclusion: This case involves an unusual clinical and radiographic presentation of a dentigerous cyst. It shows a new variant of presentation that medical professionals, specifically dentists and radiologists, should be aware of, since a dentigerous cyst crossing the midline has not been previously reported as far as we are aware. This additional knowledge is important for inclusion on differential diagnosis lists and aids in the development of a proper treatment plan.

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Laura A. Fisher et al.Effect of age, impaction types and operative time
on inflammatory tissue reactions following lower
third molar surgeryhttp://digitalcommons.unl.edu/dentistryfacpub/18
http://digitalcommons.unl.edu/dentistryfacpub/18Thu, 30 Jun 2016 12:00:41 PDTBackground: Postoperative mobidity following third molar surgery is affected by a number of factors. The study of these factors is essential for effective planning and limitation of morbidity. The aim of this study was to determine the effect of age, type of impaction and operative time on immediate postoperative tissue reactions following mandibular third molar surgery.

Methods: Consecutive patients with impacted mandibular third molar teeth were studied. All the third molars were classified according to Winter’s classification. Surgical extraction was performed on all the patients by a single surgeon under local anaesthesia. The operation time was determined by the time lapse between incision and completion of suturing. Postoperative pain, swelling and trismus were evaluated.

Results: There were 120 patients with an age range of 19-42 years. Patients in the age range of 35-42 years recorded a lower pain score (p = 0.5) on day 1. The mouth opening was much better in the lower age group on day 2 and 5 (p = 0.007 and p = 0.01 respectively). Pain, swelling and trismus increased with increasing operative time. Distoangular impaction was significantly associated with higher VAS score on day 1 and 2 (p = 0.01, 0.0, 04). Distoangular and horizontal impaction are associated with a higher degree of swelling and reduced mouth opening on postoperative review days. Vertical impaction was associated with the least degree of facial swelling and best mouth opening.

Conclusions: Increasing operating time and advancing age are associated with more postoperative morbidity, likewise distoangular and horizontal impaction types.

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Seidu A Bello et al.Identification of an immunodominant peptide from
citrullinated tenascin-C as a major target for
autoantibodies in rheumatoid arthritishttp://digitalcommons.unl.edu/dentistryfacpub/17
http://digitalcommons.unl.edu/dentistryfacpub/17Thu, 30 Jun 2016 10:55:05 PDTObjectives We investigated whether citrullinated tenascin-C (cTNC), an extracellular matrix protein expressed at high levels in the joints of patients with rheumatoid arthritis (RA), is a target for the autoantibodies in RA.

Methods Citrullinated sites were mapped by mass spectrometry in the fibrinogen-like globe (FBG) domain of tenascin-C treated with peptidylarginine deiminases (PAD) 2 and 4. Antibodies to cyclic peptides containing citrullinated sites were screened in sera from patients with RA by ELISA. Potential cross-reactivity with wellestablished anticitrullinated protein antibody (ACPA) epitopes was tested by inhibition assays. The autoantibody response to one immunodominant cTNC peptide was then analysed in 101 pre-RA sera (median 7 years before onset) and two large independent RA cohorts.

Results Nine arginine residues within FBG were citrullinated by PAD2 and PAD4. Two immunodominant peptides cTNC1 (VFLRRKNG-cit-ENFYQNW) and cTNC5 (EHSIQFAEMKL-cit-PSNF-cit-NLEG-cit-cit-KR) were identified. Antibodies to both showed limited crossreactivity with ACPA epitopes from α-enolase, vimentin and fibrinogen, and no reactivity with citrullinated fibrinogen peptides sharing sequence homology with FBG. cTNC5 antibodies were detected in 18% of pre-RA sera, and in 47% of 1985 Swedish patients with RA and 51% of 287 North American patients with RA. The specificity was 98% compared with 160 healthy controls and 330 patients with osteoarthritis.

Conclusions There are multiple citrullination sites in the FBG domain of tenascin-C. Among these, one epitope is recognised by autoantibodies that are detected years before disease onset, and which may serve as a useful biomarker to identify ACPA-positive patients with high sensitivity and specificity in established disease.

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Anja Schwenzer et al.Polishing Esthetic Restorative MateriaIhttp://digitalcommons.unl.edu/dentistryfacpub/16
http://digitalcommons.unl.edu/dentistryfacpub/16Wed, 08 Jan 2014 12:45:24 PST
When esthetic dental restorations are encountered during charting, they should be included in the treatment plan for the specific polishing procedures that are required. If the brand and type of esthetic restoration are known through the patient chart, the polishing procedures and products used should be those recommended by the manufacturer. If not possible, alternative polishing procedures should be used. A cleaning agent containing feldspar and rubber polishing cup can be used on all esthetic restorative materials with no chance of damage to the surface characterization.

The principles for polishing esthetic restorations are the same as for natural teeth. If the polishing agent used has more than one size grit polish the coarsest grit polish should be used first, followed by each successively smaller grit polish. During polishing, mixing larger abrasive particles with smaller particles will not produce the desired shiny surface because the particle sizes will mix. Each size grit must be applied separately. Therefore, to prevent each grit size from being contaminated with the previous size grit, the rubber cup or applicator must be replaced between applications. During the polishing procedure, the polishing paste should be frequently renewed in the polishing cup because the paste may dry as the binders are expressed during use, which will make the paste more abrasive.

Keeping esthetic restorative materials looking like they were just placed is a service highly valued by patients and is another reason to emphasize why dental hygiene appointments are so important.

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Caren M. BarnesEtiology of Noncarious Cervical Lesionshttp://digitalcommons.unl.edu/dentistryfacpub/15
http://digitalcommons.unl.edu/dentistryfacpub/15Wed, 08 Jan 2014 12:40:47 PST
As the number of older adults in the United States continues to grow, this change in patient demographics will profoundly affect the practice of dental hygiene. Not only are there more older adults, but they are also retaining more of their natural teeth than ever before. The risk of alveolar bone loss; gingival recession, which can lead to exposed cervical and root areas of the teeth; and tooth wear all increase with age. The confluence of these factors raises the risk of noncarious cervical lesions (NCCLs).

The prevalence of NCCLs is growing, largely due to the rising numbers of older adults in current populations. Dental hygienists are well-equipped to intercept these noncarious lesions and provide appropriate education, prevention, and treatment.

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Caren M. BarnesAn In-Depth Look at Air Polishinghttp://digitalcommons.unl.edu/dentistryfacpub/14
http://digitalcommons.unl.edu/dentistryfacpub/14Wed, 08 Jan 2014 12:35:43 PST
Air polishing has been available for four decades, however, the concept is based on a technology invented by Dr. Robert Black in 1945. Dr. Black invented the Air Dent, a device that used compressed air, water, and a highly abrasive powder to eliminate pain from cavity preparation, making anesthesia unnecessary. The Air Dent had numerous problems that could not be overcome, but Dr. Black never gave up on his idea. The technology he invented became the basis of air polishing and was first marketed in 1976. By the late 1970s, air polishing was readily available.

Air polishing represents the most significant addition to the polishing armamentarium since the introduction of handpieces and prophylaxis angles. Air polishing is accomplished by the propulsion of abrasive particles through a mixture of compressed air and water through a handpiece nozzle.1 Kinetic energy propels the air polishing paste particles against the tooth surface—removing stain and dental plaque.

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Caren M. BarnesThe Evolution of Prophy Pastehttp://digitalcommons.unl.edu/dentistryfacpub/13
http://digitalcommons.unl.edu/dentistryfacpub/13Wed, 08 Jan 2014 12:32:35 PST
Dental hygienists have many products to choose from when deciding which prophy paste is best for each patient. To date, the evidence supporting prophy pastes formulated to remineralize enamel or eliminate dentinal hypersensitivity is somewhat unclear. Most of the research has been conducted in vitro among environments that do not accurately simulate clinical conditions. Additional clinical research performed in vivo is needed to provide the evidence base necessary for effective clinical decision making.
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Caren M. BarnesShining a New Light on Selective Polishinghttp://digitalcommons.unl.edu/dentistryfacpub/12
http://digitalcommons.unl.edu/dentistryfacpub/12Wed, 08 Jan 2014 12:32:33 PST
The era of selective polishing is over. Polishing is an integral procedure provided by dental hygienists. Patients look forward to the resultant smooth, clean feeling, and dental hygienists must ensure that all patients are polished according to their individual needs—ensuring the safety of their teeth and restorations.
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Caren M. BarnesAn <i>in vivo</i> Comparison of Commercially Available Disposable Prophylaxis Angleshttp://digitalcommons.unl.edu/dentistryfacpub/11
http://digitalcommons.unl.edu/dentistryfacpub/11Wed, 18 Dec 2013 12:25:41 PST
A wide variety of disposable infection control products is being marketed including disposable prophylaxis angles. It was the purpose of this in vivo investigation to evaluate the clinical efficacy of five different brands of commercially available disposable prophylaxis angles. Utilizing a splitmouth design. 11 dental hygienists evaluated disposable prophylaxis angles while completing a routine oral prophylaxis. Fifty samples each of Brahler. Ash/Dentsply, Denticator. and Young Dental angles were compared to a control angle (Teledyne Getz). A questionnaire was completed by each operator following patient treatment (a total of 161 patients was treated). The questionnaire asked questions in which the four brands were compared to the Teledyne Getz disposable prophylaxis angle. followed by questions regarding individual performance characteristics of each brand of disposable prophylaxis angle. The comparative questions were analyzed utilizing a two-tailed z-test. and the individual performance characteristic questions were analyzed with a confidence interval. The results revealed that when the four brands of disposable prophylaxis angles were compared to the Teledyne Getz brand. the Teledyne Getz disposable prophylaxis angle performed better than the Brahler, Ash/Dentsply. and Denticator brands. However. the Young Dental disposable prophylaxis angle performed better than the Teledyne Getz brand. The results of the evaluation of the independent performance characteristics revealed that the Young Dental disposable prophylaxis angle performed more reliably than the other brands. while the Teledyne Getz disposable prophylaxis angle produced significantly less vibration than all of the other brands of disposable prophylaxis angles.
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Lisa S. Fleming et al.The Management of Aerosols with Airpolishing Delivery Systemshttp://digitalcommons.unl.edu/dentistryfacpub/10
http://digitalcommons.unl.edu/dentistryfacpub/10Mon, 16 Dec 2013 15:10:17 PST
In summary. aerosol production is inherent with airpolishers. as well as other dental equipment such as handpieces, ultrasonic scalers, and air/water syringes. By practicing prudent infection control techniques and utilizing proper operating techniques, the clinician can continue to enjoy the time-efficient and efficacious benefits of airpolishers, while ensuring a maximum protection from aerosols for the patient and the operator.
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Caren M. BarnesAn <i>in vitro</i> Evaluation of Commercially Available Disposable Prophylaxis Angleshttp://digitalcommons.unl.edu/dentistryfacpub/9
http://digitalcommons.unl.edu/dentistryfacpub/9Mon, 16 Dec 2013 15:05:17 PST
Although a number of manufacturers are marketing disposable prophylaxis angles, no literature exists regarding the mechanical efficacy and efficiency of these products. It was the purpose of this in vitro evaluation to compare and evaluate five brands of commercially available disposable prophylaxis angles for vibration, noise, heat rise, and torque. Random samples of each brand of disposable prophylaxis angle were utilized. Vibration was measured with a height gauge and running motor; noise was measured with a sound meter and heat rise was measured from 68°F on the head and body of the disposable prophylaxis angles, and torque required to destroy the gear was measured with a torque gauge. Means, standards deviations, standard errors, and coefficients of variation were computed for each of the variables tested. Results revealed that four of the brands tested (in alphabetical order) perform reliably when considering vibration, noise, heat rise, and torque: Denticator, Teledyne Getz, and Young Dental. The Ash/Dentsply had significant heat rise in the head and body. Both the Ash/Dentsply and Brahler disposable prophylaxis angles demonstrated significant vibration.
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Caren M. Barnes et al.Results of a Head and Neck Examination: Evaluation of a Tumor of the Floor of the Mouthhttp://digitalcommons.unl.edu/dentistryfacpub/8
http://digitalcommons.unl.edu/dentistryfacpub/8Mon, 16 Dec 2013 14:40:18 PST
This article reviews a solitary, well-defined tumor of the floor of the mouth. The tumor presented as a raised, elevated, sessile mass that was freely movable and soft to. the touch. The case illustrates the importance of performing a thorough head and neck examination, and formulating a differential diagnosis if any abnormality is detected. The clinical features, histopathology and responsibility of the dental hygienist in performing a thorough head and neck examination is reviewed.
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Caren M. Barnes et al.The Formin-Homology-Domain-Containing Protein FHOD1 Enhances Cell Migrationhttp://digitalcommons.unl.edu/dentistryfacpub/7
http://digitalcommons.unl.edu/dentistryfacpub/7Thu, 28 May 2009 08:32:26 PDT
Formin-homology-domain-containing proteins interact with Rho-family GTPases and regulate actin cytoskeleton organization and gene transcription. FHOD1 is a member of this family, interacts with Rac1 and induces transcription from the serum response element. In this study, we examined the effects of FHOD1 expression on cytoskeletal organization and function in mammalian cells. FHOD1 proteins were stably expressed in WM35 melanoma cells and NIH-3T3 fibroblasts. Cells expressing full-length FHOD1 demonstrated an elongated phenotype compared with vector-transfected cells and cells expressing a truncated FHOD1 (1-421) that lacks the conserved FH1 and FH2 domains. Full-length FHOD1 co-localized with filamentous actin at cell peripheries. Cells transiently expressing a C-terminal FHOD1 truncation mutant (ΔC, residues 1-1010), which lacks an autoinhibitory protein-protein interaction domain, displayed prominent stress fibers. FHOD1 (1-421) did not induce stress fibers but localized to membrane ruffles in a manner similar to the full-length protein, indicating that the FH1 and FH2 domains are required for stress fiber appearance. FHOD1 ΔC (1-1010)-dependent stress fibers were sensitive to dominant-negative RacN17 and the RhoA and ROCK inhibitors, C3 transferase and Y-27632. Stable overexpression of full-length FHOD1 enhanced the migration of WM35 and NIH-3T3 cells to type-I collagen and fibronectin, respectively. Cells expressing FHOD1 (1- 421) migrated similar to control cells. Integrin expression and activation were not affected by FHOD1 expression. Moreover, FHOD1 overexpression did not alter integrin usage during adhesion or migration. These data demonstrate that FHOD1 interacts with and regulates the structure of the cytoskeleton and stimulates cell migration in an integrin-independent manner.
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Sreenivas Koka et al.Magnitude and Pattern of Compensatory Growth in Rats after Cold Exposurehttp://digitalcommons.unl.edu/dentistryfacpub/6
http://digitalcommons.unl.edu/dentistryfacpub/6Thu, 28 May 2009 08:32:24 PDT
It is a common observation that normal growth is affected or suppressed in young individuals by environmental adversities and physical disturbances. On the other hand, when health or favorable conditions are restored, the tempo of growth promptly accelerates as if the individual is trying to make up for the growth debt incurred. Tanner has referred to this increased growth rate after diseases or starvation as compensatory or 'catch-up' growth, a topic on which he has written eloquently and fully in a number of articles (1963a, b). He considers this compensatory growth as a 'self-stabilizing' or 'target-seeking' phenomenon in the regulatory control of growth. Growth of young rats is slowed by severe cold and increased by warmth (Heroux & Gridgeman, 1958; Chevillard, Portet & Cadot, 1963). The aim of the present investigation is to show the magnitude and pattern of compensatory growth in rats after single and repeated cold exposures; to evaluate age differentials in this response; and to study the pattern and relative rate of compensatory growth in the various bony segments of the appendages.
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Marjorie Lee et al.The Development <i>in vitro </i>and <i>in vivo</i> of Fusion of the Palatal Processes of Rat Embryoshttp://digitalcommons.unl.edu/dentistryfacpub/5
http://digitalcommons.unl.edu/dentistryfacpub/5Thu, 28 May 2009 08:32:23 PDT
The congenital anomaly of cleft palate can now be reproduced by a variety of teratogenetic agents in a number of laboratory animals (Kalter & Warkany, 1959). Through the use of the induced cleft palate numerous studies have been directed toward detecting the developmental mishaps which create this defect. The work of Fraser et al. (1957) suggested that various positional factors of the developing palatal and facial structures may be the underlying cause for failure of palatal closure in mouse embryos. Walker & Fraser (1956) observed elastic fibers among the palatal processes of mouse embryos which they suggested might impart a 'shelf force' necessary for proper closure and fusion. However, Walker (1961) has since reported that there is a mucopolysaccharide in the ground substance of the palatal mesenchyme rather than an elastic fiber network. Asling et al. (1960) noted a growth spurt of the developing mandible during the critical time of palatal process closure. Along with morphological positional effects the teratogenetic agents may affect the phase of direct cellular fusion of the two palatal processes. Different teratogens may even affect different developmental sites and still create the cleft defect. Even with the various morphological studies completed upon normal and cleft embryos the exact mechanism(s) causing the cleft palate defect remain unknown.
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Thomas Moriarty et al.TGFβ3 Inhibits E-Cadherin Gene Expression in Palate Medial-Edge Epithelial Cells Through a Smad2-Smad4- LEF1 Transcription Complexhttp://digitalcommons.unl.edu/dentistryfacpub/4
http://digitalcommons.unl.edu/dentistryfacpub/4Thu, 28 May 2009 08:32:22 PDT
Dissociation of medial-edge epithelium (MEE) during palate development is essential for mediating correct craniofacial morphogenesis. This phenomenon is initiated by TGFβ3 upon adherence of opposing palatal shelves, because loss of E-cadherin causes the MEE seam to break into small epithelial islands. To investigate the molecular mechanisms that cause this E-cadherin loss, we isolated and cultured murine embryonic primary MEE cells from adhered or non-adhered palates. Here, we provide the first evidence that lymphoid enhancer factor 1 (LEF1), when functionally activated by phosphorylated Smad2 (Smad2- P) and Smad4 (rather than β-catenin), binds with the promoter of the E-cadherin gene to repress its transcription in response to TGFβ3 signaling. Furthermore, we found that TGFβ3 signaling stimulates epithelial-mesenchymal transformation (EMT) and cell migration in these cells. LEF1 and Smad4 were found to be necessary for up-regulation of the mesenchymal markers vimentin and fibronectin, independently of β- catenin. We proved that TGFβ3 signaling induces EMT in MEE cells by forming activated transcription complexes of Smad2-P, Smad4 and LEF1 that directly inhibit Ecadherin gene expression.
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Ali Nawshad et al.Effects of an Air-Powder Polishing System on Orthodontically Bracketed and Banded Teethhttp://digitalcommons.unl.edu/dentistryfacpub/3
http://digitalcommons.unl.edu/dentistryfacpub/3Fri, 05 Dec 2008 13:54:06 PST
Since the introduction of air-powder polishing systems in 1977, air-powder polishing has been shown to be an efficient and effective method for removal of stain and plaque. Air-powder polishing systems use air, water, and sodium bicarbonate to deliver a controlled stream that propels specially processed sodium bicarbonate particles to the tooth surface. It has been demonstrated that this increasingly popular technique requires less time and less physical exertion by the operator than polishing with a rubber cup and prophylaxis paste. In addition, no heat is generated with this type of system.

Studies of the air-powder polishing method have examined its efficacy in stain removal and its effects on soft tissue, hard tissue, and restorative materials. William et al. found that air-powder polishing treatment imparted a nonuniformly roughened surface to enamel. Atkinson et al. and Toevs, however, found root surfaces to be smooth after treatment with the airpowder polishing system. Furthermore, this system has been shown to produce some immediate soft tissue trauma. In all of these studies this gingival trauma has been shown to be transient and clinically insignificant.

Although air-powder polishing systems have been shown to be effective, it has been demonstrated that these systems have the potential for removing considerable amounts of resinous restorative material. On the other hand, porcelain, amalgam, and gold alloy restorations generally are not significantly affected. However, Barnes and associates did note an erosion of cement from the margin of cast-alloy restorations. The purpose of this two-part study, based on studies to date that have shown deleterious effects on resinous materials and cement, was to examine the efficacy and effects of an air-powder polishing system on orthodontically bracketed and banded teeth. Orthodontically bracketed and banded teeth certainly provide a greater challenge for routine cleaning that may be met by an air-powder polishing system.

Specifically, this study investigated the time required for removal of stain and plaque from orthodontically bracketed and banded teeth as well as the efficacy of the air-powder polishing system. In addition, the effects of airpowder polishing on composite and zinc phosphate cements used to anchor orthodontic brackets and bands were examined with a scanning electron microscope (SEM).
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Caren M. Barnes et al.The Effects of a Commercial Aluminum Airpolishing Powder on Dental Restorative Materialshttp://digitalcommons.unl.edu/dentistryfacpub/2
http://digitalcommons.unl.edu/dentistryfacpub/2Wed, 17 Sep 2008 07:56:32 PDT
Introduction: JET-Fresh™ (Dentsply International, York, PA), a new airpolishing powder that contains aluminum trihydroxide as the abrasive agent, has been introduced for use with Prophy-Jet™ (Dentsply International). Purpose: The aim of this study was to investigate the surface effects of aluminum trihydroxide airpolishing powder on a series of restorative materials. Materials and Methods: A total of 6 Class V preparations with enamel margins were created on the buccal surface of extracted human molars. The preparations were restored with Type III gold, a high copper spherical alloy amalgam, porcelain, a lightactivated hybrid composite material, a light-activated microfilled composite material, and a light-activated, resin-modified glass ionomer material. The distal half of each restoration was covered with fiberglass tape and the mesial half subjected to treatment with the aluminum trihydroxide powder via the Prophy-Jet™ for 5 seconds. After removal of the protective tape, the buccal surface of each treated tooth was replicated with impression material. Replicas were generated using epoxy resin and prepared for evaluation with scanning electron microscopy. Results: The aluminum trihydroxide produced surface alterations that were apparent visually and when viewed by a scanning microscope of the hybrid and microfilled composites and the glass ionomer restorations. The surfaces of the amalgam and gold restorations were altered, but not to the extent that the resin-based materials were. No disruption of the surface characterization of the porcelain was detected; however, with gold and porcelain materials, the aluminum trihydroxide removed notable amounts of the luting cements (the results are consistent with the data gathered with sodium bicarbonate powder). Conclusion: Aluminum trihydroxide as the abrasive agent in an airpolishing system should be avoided on resin composites, resin-modified composites, and around the margins of cemented restorations.
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William W. Johnson et al.